Why Winter Fuels Infections: Cold, Crowds & Weakened Immunity Drive Seasonal Illnesses

• Winter conditions significantly increase cases of coughs, colds, flu, and other infections due to biological and behavioral factors.
• Cold temperatures weaken the body's immune defenses by reducing blood flow to nasal passages and drying out protective mucus.
• Viruses like influenza and RSV survive longer in cold, dry air, remaining airborne and infectious for extended periods, exacerbated by indoor heating.
• Crowded, poorly ventilated indoor spaces during winter facilitate rapid person-to-person transmission of pathogens.
• Reduced sunlight, altered sleep, diet, and physical activity in winter lower Vitamin D levels and suppress overall immune function.

Why It Matters: Winter doesn't cause illness but creates ideal conditions for infections to spread and thrive.